The goal of this AREA proposal is to identify the arsenal of peptides the fish- hunting cone snail, Conus catus utilizes to subdue its prey through the rapid modulation of spinal motor activity. A prominent neuroexcitatory peptide in the venom of this species,c4a causes repetitive firing in motor neurons and disrupts rhythmic motor activity that controls swimming in zebrafish (Danio rerio). This proposal seeks to confirm the sequence and post-translational modifications of c4a and identify its molecular target on motor neurons. We have also developed the zebrafish model system to efficiently screen for novel venom peptide activities. The specific aims of this proposal are to: 1. Confirm the sequence and post-translational modifications of c4a with a focus on glycosylation. 2. Perform electrophysiological recordings on spinalized larval zebrafish and of identified spinal motor neurons in culture to confirm the molecular target of c4a and related neuroexcitatory peptides. 3. Screen C.catus venoms for additional novel peptides that modulate spinal motor activity in larval zebrafish. Completion of these goals is the first step towards our long term goals to: (1) identify the cellular and molecular targets of c4a and its homologs, (2) discover other venom peptides in C. catus, as well as additional cone snail species, that modulate zebrafish spinal motor activity and (3) determine how the signals induced by venom peptides like c4a are communicated throughout the spinal cord. The specific aims of this proposal are designed to provide a directed, integrative and comprehensive analysis of the active venom peptides in C.catus. The venom peptides identified in this proposal are novel reagents for physiological studies in zebrafish and may have a similar activity and target in mammalian neurons. In addition, there is potential for future development into novel biomedicines to aid in the treatment of debilitating conditions such as spinal cord injury. PUBLIC HEALTH RELEVANCE: This proposal sets out to identify the venom peptides used by the fish-hunting cone snail, Conus catus, to subdue its prey. The peptides will be studied using the zebrafish model system to understand how the normal activity of neurons is regulated with the potential for the development of novel therapeutics to treat nervous system disorders.